About:
Somoclu is a massively parallel implementation of self-organizing maps. It relies on OpenMP for multicore execution, MPI for distributing the workload, and it can be accelerated by CUDA on a GPU cluster. A sparse kernel is also included, which is useful for training maps on vector spaces generated in text mining processes. Apart from a command line interface, Python, Julia, R, and MATLAB are supported.

Changes:

New: The coefficient of the Gaussian neighborhood function exp(-||x-y||^2/(2(coeffradius)^2)) is now exposed in all interfaces as a parameter.

New: get_bmu function in the Python interface to get the best matching units given an activation map.

Changed: Updated PCA initialization in the Python interface to work with sk-learn 0.18 onwards.

Changed: Radii can be float values.

Fixed: Only positive values were written back to codebook during update.

About:
CXXNET (spelled as: C plus plus net) is a neural network toolkit build on mshadow(https://github.com/tqchen/mshadow). It is yet another implementation of (convolutional) neural network. It is in C++, with about 1000 lines of network layer implementations, easily configuration via config file, and can get the state of art performance.